Exam 4

Simple harmonic motion

To and fro periodic motion about its mean position

Constant time period

Periodic motion

Any motion that repeats itself after a fixed time interval

Like the moon and earth

Simple pendulum

Point of mass suspended by a long inextensible string

Hookes law

Restoring force is directly proportional to displacement

Damped simple harmonic motion

SHM of a spring whose amplitude DEC with time

Wave motion

Disturbance in a medium due to periodic motion of particles about their mean position, medium does NOT move

Transverse wave motion

Wave motion in which particles or medium vibrate in a direction perpendicular to propagational wave motion

Light waves with crest and trough

Longitudinal wave motion

In this wave motion particles of a medium vibrate in same direction as the direction of the wave motion

Travel in form of compressions and rare fractions

An example is sound waves

Compression

Area in a longitudinal wave where the particles are crowded and squeezed together

Rarefaction

Region in a longitudinal wave where particles of the medium are spread further apart, resulting in lower density and pressure

Wavelength

Measurement between crest and trough, crest and crest, and trough and trough

Measured in meters

Intensity of sounds

Represented by I

Units are W/m²

Amount of sound energy flowing per unit area per second

Threshold of hearing

Represented by Io

Minimum intensity of a sound that a normal person can hear

More than 120dB(decibels) causes pain to our ears